Friday, 15 March 2013

Why is Albert Perry's DNA so interesting?

Many
people researching their family history are interested in finding as
much as possible about the paternal line – and have resorted to DNA
testing of the Y chromosome, which passes from father to son, and
which is not found in women. Because small copying errors occur
between one generation and the next it is possible to find out how
closely related and two men are. Fossil evidence suggests that modern
man came into existence about 200,000 years ago and that all living
men shared a common “Adam” ancestor somewhere between 60 and
140,000 years ago.

That is
until Albert Perry's DNA was sent for testing by a relative – and
the laboratory carrying out the genealogical tests on his DNA were
puzzled – as it didn't fit. Further investigation suggested that
his Y chromosome was so different to yours or mine that the “Human” paternal ancestor we shared with Albert lived about 340,000 years ago – over
100,000 years before the beginnings of the modern human species.

In the talk How
Evolution made us the way we are I gave earlier this year I suggested that interbreeding of homo species played an important
part in our evolution I got excited – as the most likely
explanation is that one of Albert's ancestral mother's mated with the
male of a different homo species and the Y chromosome has passed down
the male line to Albert.

Albert
(who apparently died before the importance of his unusual DNA was discovered)
was an African-American whose ancestors probably came from a small
village in Cameroon, where 11 other men with the same unusual Y gene
have now been discovered. Interestingly this is only a few hundred
miles from the Iwo Eleru rock shelter where excavated remains suggest
that a cousin human species was still living as recently as 15,000
years ago. As we already know that early modern man had interbred
with both Neanderthal and Denisovan cousin species (in Europe and Asia) we now appear to
have another example from Africa of inter-species breeding in the last 50,000
years. This helps to support my suggestion that some human “features”
may have developed in different cousin species – and then come
together by later interbreeding – possibly on many different
occasions with many different cousin species over the 3-6 million years.

The New
Scientist also contained details of some research which suggests
that Neanderthals had bigger eyes and that more of their brain was
devoted to processing optical information that occurs in modern
humans. It is suggested that as their brain was about the same size
this may have left less room for “intelligent” thinking. There
is no comment (at least in the press reports) as to the amount of
brain devoted to speech so as far as I can see the argument could
well be that they lost out because their language skills were less
well developed. Evidence elsewhere suggested the children matured
faster – meaning a shorter “learning” time to absorb language
skills and culture. (See Royal
Society report)

Search This Blog

About Me

A.K.A. Hertfordshire Chris -
I am, by temperament, a scientist who likes to stand back and get an overview - rather than getting stuck in a narrow specialist area. I am particularly interested in how people process information and how we could design systems that fit into the way that people think.
Since I retired I have been very much involved in mental health service provision (but have recently retired from all committee work) and I run a web site at www.hertfordshire-genealogy.co.uk which provides help and advice for people whose ancestors lived in Hertfordshire.